Convective Heat Transfer Rate
Convective Heat Transfer Rate
Convection carries heat between a surface and a moving fluid. Newton’s law of cooling gives the rate from a single film coefficient.
The convective heat rate is Q = h·A·ΔT. where h is the convective coefficient, A the surface area and ΔT the surface-to-fluid temperature difference.
Inputs
h := 25 W/(m^2·K)=25 kg/K/s^3
A := 4 m^2=4 m^2
dT := 30 K=30 K
Apply Newton’s law of cooling.
Q := h·A·dT=3000 W
Results
The film coefficient h dominates and varies widely — a few W/m²K for natural air convection up to thousands for boiling. Forced flow and fins raise the heat rate.
Assumptions & limitations
- Constant film coefficient over the surface.
- Steady state.
- Uniform surface and fluid temperatures.